This application claims benefit of Japanese Application No. Hei 11-280432 filed in Japan on Sep. 30, 1999, the contents of which are incorporated by reference.
1. Field of the Invention
The present invention relates to an electronic endoscope having a treatment appliance insertion port and various operation switches formed in and on an operation unit thereof, and having a universal cord extended from the operation unit.
2. Description of the Related Art
In recent years, endoscopes having an elongated insertion unit inserted into a body cavity and having, if necessary, a treatment appliance passed through a treatment appliance channel so as to enable various kinds of examinations and treatments have widely been adopted. The endoscopes include an electronic endoscope having a solidstate imaging device such as a charge-coupled device (CCD) incorporated as an imaging means therein. The electronic endoscope converts an optical image of an object converged on the CCD into an electric signal and the electric signal into an image signal, displays an image of the object on the screen of a monitor, and thus enables observation of a lesion or the like.
A type of electronic endoscope has a soft insertion unit that includes a bending portion formed by concatenating a plurality of bending pieces. The bending portion can be angled vertically and laterally. The insertion unit can therefore be inserted into a tortuous body cavity through the oral cavity or anus. Angling the bending portion is controlled using an angling knob that is one of operation switches formed on an operation unit communicating with the proximal end of the insertion unit and filling the role of a hand-held unit.
Moreover, a universal cord accommodating a signal cable extended from the CCD or operation switch and a light guide fiber bundle is extended from a flank of the operation unit. A connector is attached to one end of the universal cord. Consequently, the universal cord is coupled to a camera control unit (hereinafter a CCU) that is an external apparatus through the connector so that the universal cord can be uncoupled freely.
The CCU has a light source and a signal processor, which are not shown, incorporated therein. The light source supplies illumination light to the electronic endoscope. The signal processor processes an electric signal photoelectrically converted from an optical image of an object by the solid-state imaging device incorporated in the distal part of the insertion unit. When the universal cord is coupled to the CCU through the connector, it becomes possible to transfer the electric signal or supply illumination light.
As shown in FIG. 1, an operation unit 100 of a conventional electronic endoscope consists of a hand-held portion 101 and an operator portion 102 located proximally to the hand-held portion 101 (upside in the drawing). The operator portion 102 has a suction button 103, an aeration/perfusion button 104, and other pushbutton switches included in operation switches, and angling knobs 105 and 106 that are also referred to as operation switches and used to angle the bending portion, which is not shown, of an insertion unit 111. Control switches 107, 108, 109, and 110 that are also referred to as operation switches are formed near the end of the hand-held portion 101 and used to control display of an endoscopic image on a display device that is not shown.
The operation unit 100 is designed to be preferably held with the left hand. A user holds the middle portion, which is not shown, of the insertion unit 111 with his/her right hand. The user introduces the distal part of the insertion unit 111 to a region to be observed in a body cavity while handling the angling knobs 105 and 106 with the fingers of his/her left hand. Otherwise, a user holds the insertion unit 111 with his/her right hand, and handles the suction button 103, aeration/perfusion button 104, and various control switches 107, 108, 109, and 110 with his/her left hand.
A user can handle the operation switches with the fingers of his/her left hand without parting his/her right hand from the insertion unit 111. The user can efficiently introduce the insertion unit 111 to a region to be observed. Moreover, since it is unnecessary to handle the various operation switches on the operator portion 102 with the wet right hand, the insertion unit 111 remains sanitary.
However, as shown in FIG. 1, a universal cord 112 having high springiness extends in a direction substantially orthogonal to the longitudinal direction of the operation unit 100. When the insertion unit 111 is introduced into a body cavity, if the insertion unit 111 is, as shown in FIG. 2, twisted in a direction of arrow A, the universal cord 112 is bent to wind about the operation unit 100. Since the universal cord 112 has springiness, the universal cord 112 bent to wind about the operation unit imposes a load, which constrains the operation unit 100 to return to its original position, on the operation unit 100. At this time, an operator must handle the operation unit 100 against the load. An unnecessarily large magnitude of force is therefore needed to manipulate the endoscope.
A discussion will be made of a case where a connector 113 attached to the proximal end of the universal cord 111 as shown in FIG. 3A and FIG. 3B is mated with a light source connector 115 formed on a CCU 114.
For example, assume that the CCU 114 is, as shown in FIG. 3A, installed to the left side of the electronic endoscope. For matching the upper and lower sides of the connector 113 attached to the universal cord 112 with those of the light source connector 115 formed on the CCU 114, the universal cord 112 must be turned 180xc2x0 to form a twist 116. The formation of the twist 116 brings about a fear that an unnecessarily large magnitude of force may be required to introduce the endoscope into a body cavity, thus invariably increasing the burden on the operator. For overcoming this drawback, the CCU 114 must be installed to have the positional relationship relative to the electronic endoscope shown in FIG. 3B.
Furthermore, when an attempt is made to handle any of the various control switches 107, 108, 109, and 110, aeration/perfusion button 104, suction button 103, and angling knobs 105 and 106 formed on the operation unit 100, a force with which the hand-held portion 101 is held may be gone. This poses a problem in that the held state of the operation unit 100 can become unstable.
A treatment appliance insertion port 117 (see FIG. 1) formed in the operation unit 100 and used to introduce a treatment appliance into a body cavity is located distally to the various control switches 107, 108, 109, and 110, suction button 103, and aeration/perfusion button 104 with the hand-held portion 101 between them. Therefore, when the insertion unit 111 is held with the right hand and the operation unit 100 is held with the left hand, it is hard to manipulate a treatment appliance such as forceps introduced into a body cavity through the treatment appliance insertion port 117. For manipulating the treatment appliance, a nurse or the like is usually asked to hold the insertion unit 111. However, when a nurse holds the insertion unit 111, an endoscopic image of an operator-intended region to be observed is hard to produce.
In efforts to improve maneuverability of an endoscope, various proposals have been disclosed in, for example, Japanese Unexamined Patent Application Publication Nos. 8-19507 and 7-100105, Japanese Unexamined Utility Model Publication No. 60-171403, and Japanese Examined Utility Model Publication No. 63-23042.
Accordingly, an object of the present invention is to provide an electronic endoscope having the characteristics of a stable hold, excellent user-friendliness, and superb maneuverability.
Briefly, an electronic endoscope in accordance with the present invention consists broadly of an operation unit, an elongated insertion unit, and a universal cord. The operation unit has a treatment appliance insertion port and various operation switches and fills the role of a hand-held unit. The insertion unit extends from the lower end of the operation unit in a direction substantially corresponding to the longitudinal direction of the operation unit. The universal cord extends from an upper part of the operation unit in a direction crossing the longitudinal direction of the operation unit at an acute angle, and accommodates at least a signal cable.